The present invention relates generally to an integral heating and cooling unit and, more particularly to a unit integrating electric heating elements and a cooling heat exchanger.
Many applications in manufacturing and other fields require controlling the temperature of a fluid. For example, in the field of plastics, the temperature for the dies used for injection molds must be carefully controlled. A heat transfer or working fluid is used to bring the dies to an elevated temperature. Sometimes, the temperature must be rapidly reduced to properly facilitate the injection molding process. In this instance, the working fluid must be quickly cooled. To heat and cool the working fluid for the dies, a separate heater and cooling heat exchanger may be used to control the temperature of the working fluid.
The common approach in the prior art to create a system that both heats and cools a working fluid typically involves plumbing or connecting a heater to a cooler. FIG. 1 illustrates a system 10 that is capable of heating and cooling a working fluid. A heater unit 40 is plumbed or piped to a cooling unit 50 to achieve both heating and cooling of a working fluid 12 according to the prior art. The working fluid 12, such as a heat transfer fluid or oil, enters the system 10 via a pipe 20. The pipe 20 connects to the heating unit 40, which includes a heating element 42. The connection of the pipe 20 to the heating unit 40 involves a joint or weld 30 to assemble. The working fluid 12 passes through the heating unit 40 where heat from the heating element 42 elevates the temperature of the fluid 12.
The working fluid 12 then leaves the heating unit 40 via a plumbing pipe 22. The plumbing pipe 22 brings the heated working fluid 12 to a cooling unit 50. One type of cooling unit 50 is a heat exchanger that uses a cooling fluid 52 to drop the temperature of the working fluid 12. The plumbing of the heating unit 40 to the cooling unit 50 with the pipe 22 involves additional joints or welds 31, 32 to assemble. The cooling fluid 52, such as water, enters the cooling unit 50 via a pipe 54. The connection of the pipe 54 to the cooling unit 50 also involves a joint or weld 33 to assemble.
In the cooling unit 50, heat from the working fluid 12 may transfer to the cooling fluid 52 depending on the heat transfer characteristics of the cooling unit 50 and the mass flow rates of the two fluids 12, 52. The working fluid 12 then leaves the cooling unit 50 via pipe 24, and the cooling fluid 52 leaves the heat exchanger through a pipe 56. The connections of the pipes 24, 56 to the heat exchanger 50 also involves joints or welds 34, 35 to assemble.
The difficult assembly of all of the components and the space required for those components presents one problem in the prior art system 10 that both heats and cools. Plumbing the heater unit 40 to the cooling unit 50 affects the number of components and amount of piping required in assembling the system 10. The increased number of components also multiplies the number of joints or welds 30-35 required, which in turn results in a greater potential for leaks to occur. Additional insulation of the system may be necessary with the increased amount of piping. Similarly, the increased number of components also adds to the cost for the system 10.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
To that end, the present invention includes an integral heating and cooling unit for controlling the temperature of a working fluid. The heating and cooling unit has an outer housing, at least one electric heating element, and a cooling heat exchanger. The outer housing defines a plenum and has a working fluid inlet, a working fluid outlet, a cooling fluid inlet, and a cooling fluid outlet. The working fluid inlet and outlet are in fluid communication with the plenum. The electric heating element is attached to the outer housing and extends into the plenum to heat the working fluid. The cooling heat exchanger is attached to the outer housing and extends through the plenum to cool the working fluid. The cooling heat exchanger is capable of receiving a cooling fluid from the cooling fluid inlet and sending the cooling fluid to the cooling fluid outlet.
The outer housing may further include a first flange, a second flange, and a tubular shell. In this embodiment, the tubular shell slides over the flanges and is welded to the outer perimeter of the flanges. The cooling heat exchanger may have a variety of designs. In one design, the cooling heat exchanger includes a tube and a plurality of longitudinal fins. The tube is attached to the first and second flanges. In a second design, the cooling heat exchanger includes a tube that is at least partially corrugated. The tube (with corrugations) is attached to the first and second flanges. In yet a third design, the cooling heat exchanger includes a spiral tube having two ends. The ends of the spiral tube are attached to the first and second flanges. In a fourth design, the inlet and outlet of the cooling heat exchanger are attached to the same flange. The cooling heat exchanger is coiled and extends within the outer housing.
In another embodiment, the present invention includes an integral heating and cooling unit for controlling the temperature of a working fluid. However, in this embodiment, the heating and cooling unit has an inverse arrangement of the heating and cooling function. The heating and cooling unit has an outer housing, a heat exchanger, and at least one electric heating element. The outer housing defines a plenum and has a working fluid inlet, a working fluid outlet, a cooling fluid inlet, and a cooling fluid outlet. The cooling fluid inlet and the cooling fluid outlet are in fluid communication with the plenum. The heat exchanger is attached to the outer housing and extends through the plenum. The heat exchanger is capable of receiving the working fluid from the working fluid inlet and sending the working fluid to the working fluid outlet. The electric heating element extends within the heat exchanger and is capable of heating the working fluid.
Another embodiment of the present invention includes a system for heating and cooling a working fluid. The system includes a controller, a working fluid flow control means, and a heating and cooling unit. The working fluid flow control means is electrically connected to the controller to control the flow of the working fluid. The heating and cooling unit has an outer housing, at least one electric heating element, and a cooling heat exchanger. The outer housing defines a plenum to carry the working fluid. The electric heating element is mounted to the outer housing and electrically connected to the controller. The electric heating element extends into the plenum and is capable of heating the working fluid. The cooling heat exchanger is mounted to the outer housing and extends through the plenum. The cooling heat exchanger is capable of cooling the working fluid.
The system may further include a cooling fluid flow control means that is electrically connected to the controller to control the flow of a cooling fluid. The outer housing of the heating and cooling unit has a working fluid inlet, a working fluid outlet, a cooling fluid inlet, and a cooling fluid outlet. The cooling heat exchanger is capable of receiving the cooling fluid from the cooling fluid inlet and sending the cooling fluid to the cooling fluid outlet. The outer housing may further include a first flange, a second flange, and a tubular shell. The tubular shell is attached to the first and second flanges. The heat exchanger for the system may also have several designs including a tube with fins, a tube that is at least partially corrugated, and a tube that is at least partially spiral or coiled.
In another embodiment of the present invention, the system may have a heating and cooling unit with an inverse arrangement of the heating and cooling functions. For instance, the system has a controller, a working fluid flow control means, and a heating and cooling unit. However, the heating and cooling unit has an outer housing, a heat exchanger, and at least one electric heating element. The outer housing defines a plenum for carrying a cooling fluid. The heat exchanger carries the working fluid and extends through the plenum to cool the working fluid. The electric heating element is mounted within the heat exchanger and capable of heating the working fluid.
In yet another embodiment, the present invention includes a method for assembling a heating and cooling unit that is capable of controlling the temperature of a working fluid. The method includes the steps of: providing a first and second flange where the flanges have a plurality of holes; providing a heat exchanger tube; welding the heat exchanger tube to the first and second flanges; providing a plurality of heating elements; welding the plurality of heating elements to the first flange; providing a tubular shell; sliding the tubular shell over the outer perimeter of the first and second flanges; and welding the tubular shell to the first and second flanges. The heat exchanger tube may have several designs including a tube with fins, a tube that is at least partially corrugated, and a tube that is at least partially spiral.
The above summary of the present invention is not intended to represent each embodiment, or every aspect of the present invention. This is the purpose of the figures and detailed description that follows.